Empyrosis is a fairly complex siege map set in a volcanic environment. The attackers must first take out three solar panels located on the roof of the defender's main base. The destruction of the panels brings down the forcefields protecting two more generators, each located in peripheral towers near the main base. When the attackers destroy these generators, the forcefields protecting the main base come down, allowing access to a third generator. With this generator's destruction, more forcefields in the towers come down, allowing the attackers to destroy two generators. These generators power forcefields that protect a final generator. The final generator powers forcefields around the switch.
In other words, there are several distinct 'power groups'; groups of power sources that must be destroyed before others can be accessed. The system is totally linear. All the power sources that must be destroyed first are labeled with 'First', those that must be destroyed next are labeled 'Second'.
A minimum of three people will be required to take down all the generators quickly. One at the main base, and one in each tower. If proper coordination is achieved, the system can come down fast. Otherwise, it will be a long game.
The attackers have a full vehicle station, although it may not prove to be a vital asset to victory.